OpenZFS on OS X

A quick question. Is there really any benefit to turn on compression when your data is primarily images and video (which are already compressed)? I'm only in the 4TB range so it may not matter but I see compression advocated a lot.

To be honest, I come from a XX-DOS background where I could recover data with low level sector editing tools where encryption and compression were not an impedance.

Are there any real datum that show that compression is beneficial where the files are already compressed? I understand that ZFS/metadata would benefit but it is unclear to me how big the benefit would be if I had to also compress a 2Gb video file as well.

Highly compressed files usually cannot be further compressed. In fact they may grow due to compressor metadata overheads. ZFS will make best effort to compress data, however it stops when it realizes that its not making a difference. Therefore you can turn compression on, knowing that ZFS will do the right thing automatically.

- Brendon

Thanks for that. I'll start turning it on for new pools then.